1. Field of the Invention
This invention relates to an oil separator for separating lublication oil from blow-by gas which comes to be produced in an internal combustion engine.
2. Prior Art
In operation of an internal combustion engine, some parts of gas in the combustion chamber leak into the crank case through a gap between the piston and the cylinder during compression and explosion strokes. This "blow-by" gas contains some volume of lublication oil constituents.
There have been proposed many devices for separating this lubrication oil constituents from the blow-by gas. For instance, in the device disclosed in the Bulletin of the Japanese Utility Model Laid-open No. 149013/1981 (Jitsu-kai-sho No. 56-149013), an oil separation case is arranged in a cylinder-head cover; a zig-zag path for the blow-by gas is formed in the case by means of arranging baffle plates; and the oil constituents contained in the gas are separated by the function of the zig-zag path which makes the flow direction of gas to change abruptly. That is to say, while the gas itself can change its flow direction smoothly, oil particles heavier than a certain degree cannot make a sudden change of its flow direction, and consequently, such oil constituents collide against the wall of the zig-zag path and adhere thereto. When the numbers of adhered oil constituents increase, they come to form drops and to fall along the wall by their own weight. The blow-by gas from which the oil constituents are excluded is sent to an intake manifold.
However, in the above way for separation, the fog-like fine oil particles tend to pass through the zig-zag path with the gas. This makes it difficult to separate and collect oil constituents completly from the blow-by gas, and consequently, the lublication oil comes to flow into the intake manifold without being separated completly. It will be apparent that these tendencies bring a drawback that the consumption volume of lubrication oil becomes large and various sensors installed to the manifold are contaminated with oil.